An irregular mare patch also known as an IMP, is a smooth, rounded, slightly mounded area, generally about 500 meters wide, occurring in the lunar maria. [1]
An irregular mare patch also known as an IMP, is a smooth, rounded, slightly mounded area, generally about 500 meters wide, occurring in the lunar maria. [1]
Due to their small size, and corresponding difficulty of observational astronomy from Earth, the first irregular mare patch discovered, Ina, was only found in 1971 after analysis of photographs taken by Apollo 15. [2] More were discovered by the Lunar Reconnaissance Orbiter, which was launched in 2009 and found about 70 more.
The origin of the irregular mare patches is uncertain. Crater counts, which can give an indication of the age of an area by the number of craters upon it, indicate that these regions can be as young as a few tens of millions of years old. It has been hypothesized by the LRO team that they are small volcanic lava flows, due to their spectroscopic similarity to other lava flows. [3] However, other analysts dispute this, noting that there are many separate patches, instead of one large patch. This would require numerous small-scale eruptions. There is also no indication of flowing, as there is in lava in other eruptions on the Moon. Even more important, the hypothesis of volcanic action is at odds with the current theory of the Moon's geology, which states that the Moon should have cooled and solidified by about 1 billion years ago, precluding further geological action. [1]
Understanding irregular mare patches may require new geological theories to be properly explained. [3] According to the current scientific theories, the Moon's small size means that its mantle should have fully solidified by about 1 billion years ago, which is backed up by seismic data. This would prevent any further geological action by the Moon's interior. [4] A recent (in geological terms) eruption would indicate that the Moon has cooled much more slowly than thought, possibly due to heat released from radioactive decay of radioisotopes in the Moon. [5]
Volcanism, vulcanism, volcanicity, or volcanic activity is the phenomenon where solids, liquids, gases, and their mixtures erupt to the surface of a solid-surface astronomical body, for example planets, moons, asteroids and comets. It is caused by the presence of a heat source inside the body. This internal heat partially melts solid material in the body or turns material into gas. The mobilized material rises through the body's interior and then, if conditions are right, the mobile material breaks through the solid surface.
Oceanus Procellarum is a vast lunar mare on the western edge of the near side of the Moon. It is the only one of the lunar maria to be called an "Oceanus" (ocean), due to its size: Oceanus Procellarum is the largest of the maria ("seas"), stretching more than 2,500 km (1,600 mi) across its north–south axis and covering roughly 4,000,000 km2 (1,500,000 sq mi), accounting for 10.5% of the total lunar surface area.
Mare Cognitum is a lunar mare located in a basin or large crater which sits in the second ring of Oceanus Procellarum. To the northwest of the mare is the Montes Riphaeus mountain range, part of the rim of the buried crater or basin containing the mare. Previously unnamed, the mare received its name in 1964 in reference to its selection as the target for the successful impact probe Ranger 7, the first American spacecraft to return closeup images of the Moon's surface.
Mare Nectaris is a small lunar mare or sea located south of Mare Tranquillitatis southwest of Mare Fecunditatis, on the near side of the Moon. Montes Pyrenaeus borders the mare to the east and Sinus Asperitatis fuses to its northwestern edge. It is 84,000 square kilometers in size.
The lunar maria are large, dark, basaltic plains on Earth's Moon, formed by lava flowing into ancient impact basins. They were dubbed maria by early astronomers who mistook them for actual seas. They are less reflective than the "highlands" as a result of their iron-rich composition, and hence appear dark to the naked eye. The maria cover about 16% of the lunar surface, mostly on the side visible from Earth. The few maria on the far side are much smaller, residing mostly in very large craters. The traditional nomenclature for the Moon also includes one oceanus (ocean), as well as features with the names lacus ('lake'), palus ('marsh'), and sinus ('bay'). The last three are smaller than maria, but have the same nature and characteristics.
Rille is typically used to describe any of the long, narrow depressions in the surface of the Moon that resemble channels. The Latin term is rima, plural rimae. Typically, a rille can be several kilometers wide and hundreds of kilometers in length. However, the term has also been used loosely to describe similar structures on a number of planets in the Solar System, including Mars, Venus, and on a number of moons. All bear a structural resemblance to each other.
Taruntius is a lunar impact crater on the northwestern edge of Mare Fecunditatis. It was named after ancient Roman philosopher, mathematician and astrologer Lucius Tarutius Firmanus. To the northwest is the lava-flooded crater Lawrence, and to the north lie the craters Watts and da Vinci.
Mairan is a lunar impact crater that is located on a highland peninsula between Oceanus Procellarum to the west and Mare Imbrium to the east. To the north-northeast is the comparably sized crater Sharp. Northwest of Mairan is the heavily eroded Louville.
Bowditch is a lunar impact crater that lies on the far side of the Moon, just beyond the eastern limb. It is located on a region of the lunar surface that is brought into view due to libration, but at such times the area is viewed from the edge and so not much detail can be observed. It lies just to the north of the small Lacus Solitudinis lunar mare, between the craters Titius to the southwest and Perel'man to the east-northeast.
Lacus Felicitatis is a small patch of the lunar surface that has been inundated by flows of lava, leaving a level patch with a lower albedo than the surrounding ground. It is located in Terra Nivium, an area of continental ground to the north of the Mare Vaporum. About 70–80 km to the northeast of this area are the Montes Haemus, along the southwestern edge of the Mare Serenitatis.
Ina is a peculiar small depression on the Moon, in Lacus Felicitatis. It is D-shaped, 2.9 km × 1.9 km wide and 64 m deep.
The geology of Mercury is the scientific study of the surface, crust, and interior of the planet Mercury. It emphasizes the composition, structure, history, and physical processes that shape the planet. It is analogous to the field of terrestrial geology. In planetary science, the term geology is used in its broadest sense to mean the study of the solid parts of planets and moons. The term incorporates aspects of geophysics, geochemistry, mineralogy, geodesy, and cartography.
The geology of the Moon is quite different from that of Earth. The Moon lacks a true atmosphere, and the absence of free oxygen and water eliminates erosion due to weather. Instead, the surface is eroded much more slowly through the bombardment of the lunar surface by micrometeorites. It does not have any known form of plate tectonics, it has a lower gravity, and because of its small size, it cooled faster. In addition to impacts, the geomorphology of the lunar surface has been shaped by volcanism, which is now thought to have ended less than 50 million years ago. The Moon is a differentiated body, with a crust, mantle, and core.
Lacus Veris is a small lunar mare on the Moon. In selenographic coordinates, the mare centered at 16.5° S, 86.1° W and is approximately 396 km long. The mare extends along an irregular 90° arc from east to north that is centered on the Mare Orientale, covering an area of about 12,000 km2. Author Eric Burgess proposed this mare as the location of a future crewed lunar base, citing a 1989 study performed at the NASA Johnson Space Center.
Volcanic activity, or volcanism, has played a significant role in the geologic evolution of Mars. Scientists have known since the Mariner 9 mission in 1972 that volcanic features cover large portions of the Martian surface. These features include extensive lava flows, vast lava plains, and the largest known volcanoes in the Solar System. Martian volcanic features range in age from Noachian to late Amazonian, indicating that the planet has been volcanically active throughout its history, and some speculate it probably still is so today. Both Earth and Mars are large, differentiated planets built from similar chondritic materials. Many of the same magmatic processes that occur on Earth also occurred on Mars, and both planets are similar enough compositionally that the same names can be applied to their igneous rocks and minerals.
Taurus–Littrow is a lunar valley located on the near side at the coordinates 20.0°N 31.0°E. It served as the landing site for the American Apollo 17 mission in December 1972, the last crewed mission to the Moon. The valley is located on the southeastern edge of Mare Serenitatis along a ring of mountains formed between 3.8 and 3.9 billion years ago when a large object impacted the Moon, forming the Serenitatis basin and pushing rock outward and upward.
The Compton–Belkovich Thorium Anomaly is a volcanic complex on the far side of the Moon. It was found by a gamma-ray spectrometer in 1998 and is an area of concentrated thorium, a 'fertile' element. Lunar rock samples from the Apollo missions reveal that most lunar volcanism occurred around 3 to 4 billion years ago, but this feature could have formed as recently as 1 billion years ago due to the unknown history of the Moon's far side.
A crater is a landform consisting of a hole or depression on a planetary surface, usually caused either by an object hitting the surface, or by geological activity on the planet. A crater has classically been described as: "a bowl-shaped pit that is formed by a volcano, an explosion, or a meteorite impact". On Earth, craters are "generally the result of volcanic eruptions", while "meteorite impact craters are common on the Moon, but are rare on Earth".
Volcanism on the Moon is represented by the presence of volcanoes, pyroclastic deposits and vast lava plains on the lunar surface. The volcanoes are typically in the form of small domes and cones that form large volcanic complexes and isolated edifices. Calderas, large-scale collapse features generally formed late in a volcanic eruptive episode, are exceptionally rare on the Moon. Lunar pyroclastic deposits are the result of lava fountain eruptions from volatile-laden basaltic magmas rapidly ascending from deep mantle sources and erupting as a spray of magma, forming tiny glass beads. However, pyroclastic deposits formed by less common non-basaltic explosive eruptions are also thought to exist on the Moon. Lunar lava plains cover large swaths of the Moon's surface and consist mainly of voluminous basaltic flows. They contain a number of volcanic features related to the cooling of lava, including lava tubes, rilles and wrinkle ridges.